Electrical phonograph reproducer and the like



July 6 1926.

C, W. PETERSON ELECTRICAL PHONOGRAPH REPRODUCER AND THE LIKE Filed Feb. l, 1926 Fly. 3 8

f lo` Fig. 4.

IN1/EN TOR.

rnsnaaiuiy e, i i 1,591,233 .UNITED .serai-Es PATENT oFFici-z. i i w. Panneau, or variieren, anoniem. l i

' rammen; rnonoeaun aaraonuoan 'rn aina. spannen aina rem-any i, iene. .semi iro. sima i .y My invention relates to means for the magnet2 5 is the pivot spring", 6 is a para- 4 'elimination of the reproduction of undesiramagnetic connection between the pivot ble noises in sound' re roducers: such as spring and the permanent magnet, 7 is the 4the scratch of the sty us on phonograph stylus holder or needle chuck, 8 is a stylus 00 records, scratchy static noises in radio loud or needle which follows the 4wavy grooves speakers, and overtones usually superimof the record, 9 is a coil surrounding the upon reproduced music due to the amature, 10 is 'what Iffcall the deadener,

natural period of vibration of various memand 11 shows the direction in which the bers of the reproducers -themselves, without waves in the record vibratevthe stylus and hampering or distorting the reproduction armature.x y

of the desired sounds. In Fig. 1, as in any other magneto elecfurther object of my improvements in tric phonograph reproducer, the vibrations electricalphonograph reproducers relates to of the st lus on the record are transmitted a means of making the armature and stylus to and vibrate the armatiire,which lengthens 'holderl extremely light so as to 4oiier pracand shortens the air ga s between it and the ticall no inertia resistance to thestylus in permanent magnet po es causing an alter- .exacty following the wavy grooves on the nating magnetic llux to iow thru the armareco and yet stiff enough so as not to bend ture and coil, which induces an alternating in transmitting the vibrations fromthe rec- E. M. F. in the coil in correspondence with 75 ord and-thereby distorting the reproduction. the vibrations on the record. 4The differ- ',Ihefnovelmeans ,by which I accomplish ence between my reproducer, Fig. 1, and the objects of my invention will Abe clearly those previously known, lies in the dead- .understood from the following description, ener 10, and in the construction of the 4taken in .connection with the acompanying armature 3, stylus holder 7, and pivot 30 drawings forming part of this specification, spring 5.

.with the further understanding that while The urpose of deadener 10, Fig. 1,'is "the drawings show a practical form'of my twofol and may be explained as follows:

invention, the latter is not confined to any Without the deadener 10 the armature 3 strict conformity with the showing of -the has a natural period of vibration determined 35 drawings, but may be changed and modified, bg' the weight of the vibratinIg members and t e 5 n so long as such changes and modifications strength of spring re reducing Ycome within the scope of the appended selections all of the notes in tiie record claims. which are of the same pitch as the natural In the drawings period of the armature will be unduly am- Figure 1 is a front view of a ma eto plied and hence distorted reproduction reelectric phonograph reproducer containing sults. Also if stylus holder 7 and armature my improvements. 1 3 are light enough to vibrate freely at high Figure 2 is an end view of what I call` frequencies, so that the highest musicalthe deadener in place around the end of notes will be reproduced, the scratchv the armature and showing the various zones noise, so common in phonographs, will also f ofvibration. be reproduced. B novel' construction and Figure 3 is a vertical cross section of a careful selection o materials in deadener three ply deadener in place on an arma- 10, which I place somewhere in the viture. bratin system, as for instance on the arma- 100 l -Figure 4 is an end view of a rubber dead- -ture right above the stylus holder 7, I overener which has threads moulded in itin one come both of the ditliciilties described above. direction. l The action of the deadener whereby it Figure 5 is a longitudinal sectional view accomglishes these results is quite com liof the armature and stylus holder used in cated ut ma be` explained as follows: t the reproducer shown in l showing its us imagine t e deadener being a chunk of novel, unusually light, an inflexible conrubber of the ap roximate shape shown in struction. l Figs. 1 and 2. n accomplishing the rst Referring to Fig. 1; 1 is a case, 2 .a perresult,-i. e., that of destroying natural manent ma et, 3 an armature of paramagperiods of vibration of the armature' system, 11 netic material, 4 are short air gaps between the rubber acts as a dead weight hung on the amature and the N. and S. poles of the the" vibrating system and kills the former in' f ntomas natural period due yto the change' in 1weight. any lexcess weight on the vibrating members A new' natural period of vibration is not at high frequencies as the vibrationsonly formed because the we ihtv added in .the atleet the deadener inside of zone (a) Fig. form of .rubber has no etinitefvalue, but 2, for instance. To y celow notes cor- I varies for each different fr uency, as can rectly, the vibrating'`V A'stain must be very 70 be explained b reference to ig. 2. When limber. My elastic deadener of large armature 3 is' ing v ibratedat a hi h frediameter as shown in Fig. 2, oers very quency, deadener 105bilers considera le inlittle resistance t o. movements of armature /ertia to being vibrated as4 a whole, and 3 at low frequencies, as the full elastic value l because of the elastic nature of thev rubber, ofv the whole deadener comes into play and 'I6 a balance between elastic force and inertia allows vibration even outside of zone S). 'is .reached by the vibrations 4only travelin A confined deadener of small diameter as out as far as, for instance, dotted circle (ag tlie effect 'of preventing the reproduction of in the rubber. Hence at this freI uency, low notes but does not hinder the reproducll only the weight of rubber out as ar as tion of highnotes and hencecauses distor- 80 vcircle (a) is added to the vibrating system. tion. s At a much lower fre uency the weight of n Othermaterials besides rubber make Igood rubber out of circle c) may be ad ed to deadeners. Soft leather, felt, felts orthe vibrating system. To, obtain a harmful clothssoaked with liquids, liquids held in I0 natural period in the vibrating system we a container around the amature, etc., may B5 as possible. -My' must have both a definite strength of spring be. mentioned. Sometimes an advanta us and a definite weight vibrated at all freresult can be btained by making the eadquencies. I f ener out of several materials: yFor instance, The same rubber deadener accomplishes Fig. 3vshows in cross section a deadener the second result, that of preventing the remade out of a layer of rubber 13, a layer 90 reduction of the record scratc ,'as folof felt 14, and another layer of rubber 15.k

ows:-Record scratch is a jumble of dif- Fig. 4 shows one of the best deadener conferent frequencies, -v all practically above structions, which is rubber with threads 16 3,000 'cycles per second. The hi hest notes moulded into it with threads in one direcwe have to reproduce, to give fu character tion. This deadeneris elastic in directions 95 to re roductions is 3,000 or so lcycles per 1l and relatively inelastic in directions 12 secon. From this it can be seen that, if and prevents any vibrations of the armawe can` find some way of reveting the ture 1n other directions than the correct armature from being vibrate at frequencies plane of vibration 11. This adds to pureabove 3,000 but not hinder its vibration beness or reproduction and, in reproducers 10 low 3,000 we will be able to prevent the rebulli llke 1g. 1, adds strength so that if production of the scratch andnot harm the the reproducer iS dropped on a record the reproduction of the music, A deadener armature 3 or spring 5 will -not be damaged. of rubber, when placed as I have shown it, My novel construction of the amature 40 produces just this effect to a. remarkable deand. St lus holder iS Shown in the lon 10| grec, due to the fact that, rubber loses most, tudina cross sectional view Fig. 5. In t is of its elastic properties whenv subject to viarmature and Stylus holder the two things brations over 3,000 per second, and acts as a Sought for were extreme lightness and exrigid body preventing most movements of treme Ilgldlty. The hghtneSS iSvneCeSSa A the armature of over 3,000 cycles per second, `in orderthat the stylus may accurately fo llt This pro erty 0f rubber muy be hkened to low the wavy record groove no matter what the well nown property of paving pitchthe frequency, and the ri idity is required A that when a chunk of pitch is hit a sudden 1n Order that there Will n0 bending 0f rap with u hammer, it, acts as a brittle Solid the. armature under the stress ofl vibration,

and flies t0 pieces like glass, The Same fvhlch 'WOllld PIQdllCe undesll'b1e-0v9lt0n0s l chunk though, if acted upon by a slow force, 1n the reproduction.

may be bent into any shape desired and acts Maklllg thearmture 0f tubular section more like, a'semliquid than u, Solid, A fulfills both of these requirements. My deadener of this same action may -be used novel stylusliolder, which is a chuck, is also 56 in radio loud speakers t0 help revent several .times lighter than the conventional 120 the reproduction of scratchy soun ing at set screw t pe. I make the armature, stylus mospheric static noises without hindering holder an pivot spring all out of one piece lthe reproduction of' the musical tones. .fof iron as is seen in Fig. 5. The armature is Making the"deadener out o f elastic mabored'hollow, as 17, from the upper end,

00 ter'ialand of large diameter as shown in leaving a very thin-wall 18. The chuck end 125 'the res has two i more advantages beis then threaded, as shown at 20, and bored sides t ose already mentioned: First, to reat 19 to t the'needle. A slot 21 cut thru produce correctly the desired hi h musical the end makes the chuck ilexible so'that it notes the vibrating-system must as light can contract and clam .the needle when' deadener. does not .hang chuck aut 7 y is 'screws j up` tight.' lastly l" the upper end of armature tube 18 is collapsed flat and forms fulcrum spring 5. This spring is thin and wide and allows vibration of the armature only in a direction at right angles to its plane, and also is strong enough to hold the armature away from touching either the N. or S. pole of magnet 2, Fig.`

Having thusl described' my invention, what I cleim as new and wish to protect by;A LettersPatentis fr .f "'f. 1.'In a sound converting apparatus, a dampening member With threads, or thc like, running thru it in one direction making it more elastic in one direction than the other. f l

2. In a magneto electric phonograph re-. producer, an armature, pivoting spring, and stylus holder tube all made out of one piece of paramagnetic metal.

3. In a magneto electric phonograph reproducer, an armature of hollow tubular form and a pivoting vspring made by collapsing flat, part of the same tube.

4. In a phonograph reproducer, a hollow tubular stylus bar, a rubber deadener mounted thereon, and a contracting jaw stylus chuck connected thereto.

5. In a magneto electric phonograph re- 50 producer, a permanent magnet terminating producer, a

,23s rf1;

in N. and S. poles, an armature of paramagnetic material swinging between said poles, with a pivoting spring at one end connecting it with the neutral portion of the magnet and a stylus holder at its other end, an armature coil around said armature, and a deadener in contact with said armature.

6. In a magneto electric phonograph re-` producer, thev combination of a permanent wmagnet terminating in N. and S. poles, a hollow' tubular armature of paramagnetic material swinging betweensafid lpoles vwith a pivoting spring at one endl ,connecting-Wit* withthe neutral portion of the magnet and a contracting'llchuck stylus holder at its other end, anparmature 'coil around said armature, and a damping member on said armature abovefvsaid chuck. f

7. In a magneto-electric phonograph repermanent magnet terminating in N. and Sp'poles, an* armature of paramagnetic material movable with relation to the magnet poles and having a paramagnetic connection at one end of the armature, with the magnet at the neutral portion thereof, 'a

stylus holder at the other end of the arma'- ture, an armature coil about said armature, and a deadener 1n contact with sald armature.

CHARLES W. PETERSON. 

